Studies are directed to an understanding of intestinal chylomicron formation using an in-vivo rat model absorbing fat at high rates. Understanding of the assembly of the phospholipid protein cholesterol of the chylomicron is a particular objective. We plan to explan studies of chylomicron protein synthesis and characterize more fully the differences between chylomicron particles derived from proximal and distal small intestine. Such studies are also planned in human subjects. We plan to start studies of the initial metabolic fate of chylomicrons of different composition in recipient animals. In addition, it is planned to pursue studies of abnormalities of intestinal triglyceride emulsion formation and investigate whether the high incidence of total body calcium depletion in patients post-gastrectomy may be due to the failure of normal calciferol absorption. Such defects in calciferol absorption may result from impaired emulsification and/or ineffective micellarization in the intestinal lumen.